Azo dye and method for its preparation



UNITED STATES PATENT OFFICE AZO DYE AND METHOD FOR ITS PREPARATION Mordecai Mendoza, West Didsbury, England, assigner to Imperial Chemical Industries Limited, a corporation of Great Britain No Drawing. Application August 23, 1932, Serial No. 630,059. In Great Britain September 21,

8 Claims. (Cl. 260-80) This invention relates to azo dyestufis and least one sulfonic acid group and may contain as more particularly refers to disazo dyestufis 'espemany as three such groups. In the event that cially adapted for dyeing wool and other animal one naphthol radical contains three sulfonic acid fibers, and methods for their preparation. groups, the other naphthol radical shouldcontain It is an object of this invention to produce dyes only one sulfonic acid group. 5 capable of imparting to wool and other animal These sulfonic acid groups may occupy various fibers uniform shades of excellent. fastness to positions on-the naphthol radical provided that milling, stoving, washing and light. A further coupling with the tetrazotized meta-tolidine is object is to prepare dyes suitable for dyeing aninot thereby prevented from taking place. In

* 10 mal fibers in beautiful even shades, particularly order to produce a clear red dyeit is essential 10 shades of red. Additional objects will appear that not more than one naphthol radical should hereinafter. have the sulfonic acid group in position 8 with These objects are accomplished by the process respect to a 1- or 2-hydroxyl group. It is not of the present invention wherein meta-tolidine necessary that any sulfonic acid group occupy (2-2'-tolidine) is tetrazotized and coupled with this position, but in case such position is occupied 15 one equivalent each of two diiferent sulfonated' by a sulfonic acid group, care should be taken 1 naphthols, t that the other naphthol radical should not be The invention may be more completely undersimilarly substituted, otherwise instead of a red stood by reference to the following example in dyean orange dye wouldbe produced. Theseinwhich the quantities are stated in parts by structions show how to obtain either a red or an 20 weight: orange dye by a proper selection of naphthol com- Example pounds substituted with sulfonic acid groups. Other red dyes similar to that described in the sin-122m: sarcasm exammemmepmd by tetrazotized meta-tolidine with substituted 5 was stirred into a well cooled solution of 34.8 parts of the di-sodium salt of 2-naphthol-6-8- naphthol compounds according to the instructions previously given. For instance, to produce isulfonic acid and 27 parts of sodium carbonate clear dye of exceptional stability tetraz in 400 parts of water. Coupling, which was altized metwtondfne may be coupled i any of lowed to proceed for about one hour at 0-5 0., resulted in the formation of a bright yellowishthe substituted naphtmlsred solution. There was then added a solution v of 34.8 parts of the di-sodium salt'of 2-naphthol- 'P base coupled 3-6-disulfonic acid in 300 parts of water and the mixture was stirred for a further 12 hours. zmondlm BD t 01-6,8-disulfonic acid.

A deep red solution was obtained from which 2740mm ggggggggggggggg ig 33g: 35 the disazo dyestuff was isolated by addition of i gg gggijg gggig gigcommon salt. When dried and ground it was z-y'wudim {gnaggtgol-s-suliouic acid: a. deep red powder. Wool was dyed by it from amended. i Bcid' an acid bath in a beautiful even clear red shade. nap o tome acid' The dye bath exhausted extremely well and the These are on! y a few of the compounds which q iw g g gi to washmg' stovmg' alka" may be produced without departing from the line m1 ling all a m scope of the present invention but they are sufll- Accordmg totms mven on coupling sho d be ciently illustrative so that no difliculty should be carried out in alkaline solution. Each naphthol encountered in selecti radical should contain at least one sulfonic acid other compounds gg f ga g p, a both naphthol radicals Should The dyes produced herein are exceedingly well tain no more than four sulfonic acid groups. In adapted for dyeing animal fibers. They impart other words, in carrying out the process of this beautiful uniform colors, particularly in the vainvention a naphthol radical must contain at rious shades of red, and by a proper selection of M) coupling components may be made to impart orange shades to the textile material. They are imite stable to washing, stoving; alkaline milling and light; exhaust extremely well; and are ex ceptionally well adapted for dyeing wool, felt, silk: or other material of animal origin.

As many apparently widely differentembodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appendedclaims.

I claim:

1. A process for producing azo dyes which comprises couplingtetrazotized m-tolidine with one equivalent each of two dissimilar naphthol-sulfonic acids.

2 A process for producing azo dyes which comprises coupling tetrazotized 'm-tolidine with one. equivalent each of two dissimilar beta-naphthol-sulfonic acids, both equivalents having sub- A stituted thereon no more than four sulfonic acid 3. The process of claim 2 wherein one naphthol-sulfonic acid has a sulfonic acid group in position 8 with respect to a z-hydroxyl group.

4. A process for producing an azodye which comprises coupling tetrazotized m-tolidine with.

one equivalent of 2-naphthol-6-8-disulfonic acid and one equivalent of 2-naphthol-3-6-disulfonic acid..

5. A20 dyes having formula:

wherein A and B represent the radicals of dis- 10 similar naphthol-sulfonic acids.

6. A20 dyes having the' following general the following I general formula:

m In no x no wherein x represents hydrogen or a sulfonic acid group,both naphthcl radicals having substituted thereon no more than four sulfonic. acid groups and wherein the naphthol radicals are dissimilar.

7. The products defined in clan n 6 wherein one naphthol ri'iciigcail v has a sulfonic acid group in position 8 with respect to a z-hydroxyl group.

8. Au azo dye having the following formula:

' on Q m cm 110 no 0, u

uonnzciirmnozn. 

